PH0LADID2E. 
385 
8 °metimcs follow the thread of the wood ; sometimes they ent it at 
ll ght angles ; the miners, in fact, change their route the momeut they 
rilee t in their way either the furrows hollowed out by one of their con- 
veners, or some ancient and abandoned gallery. By a strange kind of 
distinct, however multiplied may he their furrows or tubes in the same 
Piece of wood, they never mingle— there is never any communication 
tween them. The wood is thus attacked on a thousand diverse 
P°mts, until it is invaded and its entire substance destroyed. It is 
8e cret ravages of this kind that the piles and other submarine con- 
'Actions upon which bridges are built are often riddled and perforated, 
hey appear to all outward examination as solid and perfect as at the 
foment they were first driven ; but they yield to the least effort, 
ringing ruin and destruction on the edifices they support. Ships 
■ lave been thus silently and secretly mined, until the planks crumbled 
; ilto dust under the feet of the sailors. Others have gone down with 
heir crews, entirely caused by the ravages of these relentless enemies, 
"duch are terrible from their very littleness. 
M. Quatrefages, who has minutely studied the organization and 
habits of the Teredos in the Port of Saint Sebastian, reports the fol- 
°wiug fact, which will give the reader some idea of the rapidity with 
' v hich these dangerous molluscs pursue their ravages : — 
A boat, which served as a passage-boat between two villages on the 
C ° ast , went down in consequence of an accident at the commencement 
spring. Four months after some fishermen, hoping to turn her 
J^terials to advantage, raised the boat. But in that short space of 
' ,lle the Teredos had committed such tavages that the planks and 
‘fibers were riddled and worm-eaten so as to he totally useless. 
At the beginning of the eighteenth century, half the coast of 
dland was threatened with annihilation because the piles which 
Su Pport its dikes and sea-walls were attacked by the Teredo, and it 
f'oved no contemptible foe. Many hundreds of thousands of pounds 
; ' ere expended in order to avert the threatened danger. Fortunately, a 
oxer attention to the habits of the mollusc has brought a remedy to 
m ° s t formidable evil ; the mollusc has an inveterate antipathy to 
and timber impregnated by the oxide of iron is safe from its 
^ages. This taste of the Teredo being known, it is only necessary, in 
' er to scatter this dangerous host, to sink the timber which is to be 
merged in a tank of prepared oxide of iron — clothed, in short, in a 
2 c 
